Good & Green: Sun House

An eco-friendly design merges easily into its woodsy setting

When New Yorkers Jeff Hubbard and Purvi Sevak found an 11-acre parcel on a birch-blanketed mountain in southern Maine, they snapped it up, envisioning building a retreat for summer vacations and winter weekends. The eco-conscious duo wanted a simple cabin that would meld into the landscape and use natural resources wisely. They enlisted Derek Bloom, a Massachusetts architect who specializes in sustainable design, to create an energy-efficient home using local materials.

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Bloom specified native stone and wood species, and suggested passive solar techniques to naturally warm and cool the house. To learn how best to achieve the desired temperature variations, he used a 3D computer model to gauge the home's solar exposure at different times of the year according to latitude, slope, and tree coverage. Based on the results, Bloom faced the house's main living area to the southwest to take advantage of the sun's low position in the colder months, and used deep roof overhangs to shield the rooms from the stronger rays of summer. "Inside the house in winter, you can feel a lot of heat radiating from materials that the sun warmed up," says Bloom. "And in the middle of a summer day, when the great room is in shadow, it's a cool, comfortable place to be."

Owner Jeff Hubbard works in the kitchen of his Bethel, Maine, home. Built a year ago, the three-bedroom, 2,700-square-foot house has an open layout and a strong connection to the outdoors. The plan takes advantage of passive solar design principles, harnessing the sun's energy to keep Hubbard's family warm during the winter—without a hefty price tag.

For the interior finishes, architect Derek Bloom specified dense, dark materials that retain heat. "The black slate floor and the bluestone fireplace soak up the sun's energy all day to keep its warmth even when the outdoor temperature drops at night," he explains. The stored solar heat supplements a radiant-heating system installed beneath the flooring. The darker-colored elements, including charcoal-stained maple kitchen cabinets and black granite counters, as well as a custom-made steel stair-and-railing unit, contrast with the white pine–paneled walls. "The homeowners didn't want a lot of drywall or fussy molding details," Bloom says. "They wanted a sense of being in the woods." The drywall they did use, on the back wall and mezzanine office, is coated with a flash of red paint. The office appears to float above the great room because the former is supported by a narrow steel tension rod attached to reinforced roof rafters. "A big column in the middle of the room would have compromised the open feeling," Bloom explains.

On the Southwest-facing rear of the house, an array of fixed and operable insulated windows with low-emittance coatings provides the great room with ventilation, natural light, and, in the colder months, a means to gather heat from the sun. All of this helps to reduce the family's reliance on electricity and power. The staggered fenestration pattern was both a style decision and a cost-saving solution. "The challenge was to create a 25-foot-high glass wall out of a bunch of small, standard-size windows," says the architect. He juggled the available models (the largest is 5 by 5 feet) and played with placement, mixing vertical and horizontal shapes.

Deep roof overhangs, 12 feet over the rear porch and 2 feet over the sides of the building, protect the living spaces from the full strength of the summer sun, but allow plenty of light and warmth in the winter. Bloom covered the house in vertical, untreated slabs of red-cedar siding, a naturally rot- and bug-resistant material that will gradually weather to a silvery gray. Steel covers the gabled roof, and four 15-foot-tall, rough-cut granite piers from a nearby quarry support the porch. Using local materials like these eliminates fuel costs and emissions that stem from transporting materials long distances. The "lawn-free" landscaping plan consists of native ground cover and plantings that don't need irrigation. To minimize erosion—as well as disruption of the forest's natural drainage patterns—no paving or hardscaping was done.

The home's overall design emphasized a connection to nature. In the spacious master bathroom, located on the house's second level, Bloom placed a large window behind the soaking bathtub to enable bathers to gaze out into the woods. The window overlooks an exterior passageway connecting a walk-in shower to the home office. "If you leave that porch door open when you shower, you can get the breeze and the sun, and it really feels like you're bathing outdoors," says the architect. To conserve water, Bloom specified low-flow aerators for the lavatory faucets.

Most architectural firms that use computer-assisted design (CAD) programs can conduct sun studies to predict how sunlight will affect a house in various seasons, and thereby determine the best site orientation for taking advantage of passive solar energy. The image on the left depicts conditions at 11 a.m. in the summer, when the home's overhangs can block the high-angle sun and cast shadows that keep the house's interior cool. The image on the right shows 11 a.m. in winter, demonstrating how a southwest orientation with a wall of windows allows heat and low-angle light to enter the home.